A fan

The present invention relates to a ventilation device. In particular, but not exclusively, the present invention relates to a home fan, such as a desk fan, for creating air circulation and air current in a room, office or other home environment.

[0002] Many types of domestic fans are known. A conventional fan normally includes one set of blades or wings mounted to rotate around an axis and drive a device mounted around the axis to rotate a set of blades. Domestic fans are available in a variety of sizes and diameters, for example a ceiling fan can be at least 1 m in diameter and is usually mounted suspended from the ceiling and positioned to provide downward airflow and cooling throughout the room.

[0003] Desk fans, on the other hand, are often 30 cm in diameter and are usually free standing and portable. In a standard desk fan system, a single set of blades is located close to the user and the rotation of the fan blades provides a stream of air current forward in the room or in a part of the room and towards the user. Other types of fan can be attached to the floor or mounted on the wall. The movement and circulation of air cause a so-called "cool breeze" or breeze and, as a result, the user feels the cooling effect, as heat is dissipated by convection and evaporation. Fans such as those depicted in USD 103,476 and US 1,767,060 are suitable for placing on a desk or table. US 1,767,060 describes a desk fan with an oscillating motion function that is designed to provide air circulation equal to or greater than prior art fans.

[0004] A disadvantage of this type of system is that the forward air current flow generated by the rotating fan blades is not uniformly felt by the user. This is due to differences on the entire surface of the blade or on the entire outer face of the fan. An uneven or "variable" air flow can be felt as a series of bumps or blasts of air and can be noisy. Another disadvantage is that the cooling effect caused by the fan reduces the distance to the user. This means that the fan should be placed very close to the user so that the user can benefit from the fan.

[0005] In a home environment, it is desirable that the devices be as small as possible and take up little space due to space restrictions. It is undesirable for parts to protrude from the device or for the user to touch any moving parts of the fan, such as blades. Some systems have safety features, such as a cage or blade cover to protect the user against injury from moving parts of the fan. USD 103,476 shows the type of cage around the blades, however, sheltered blades can be difficult to clean.

[0006] Other types of air fan or circulator are described in US 2,488,467, US 2,433,795 and JP 56-167897 (Closest prior art). The fan of US 2,433,795 has spiral grooves in a swivel housing instead of blades. The circulation fan shown in US 2,488,467 releases an air stream from a series of exhaust ports and has a large base containing a motor and a blower or fan creating an air stream.

[0007] Placing fans, such as those described above, near the user is not always possible, because the substantial shape and design mean that the fan occupies a significant portion of the user's work space. In a special case of a fan placed on or near a desk, the fan body or base reduces the space available for office work, a computer or other office equipment. Often, many other devices must be in the same area, close to a power source and very close to other devices, in order to easily connect and reduce operating costs.

[0008] The shape and design of the fan on the desk not only reduces the work space available to the user, but can block daylight (or artificial light) access to the desk area. A well-lit desk is necessary for manual work and for reading. In addition, a well-lit area can reduce eye fatigue and related health problems that can result from prolonged work in low light.

[0009] The present invention is intended to provide an improved ventilation assembly that eliminates the disadvantages of the prior art. It is an object of the present invention to provide a compact ventilation assembly that, in use, generates an air flow at an equal rate over the exhaust emission area of ​​the fan.

[0010] According to the invention, there is provided a bladeless fan assembly for creating an air current, a fan assembly comprising an outlet opening mounted on the base housing for causing air flow through said outlet opening, an outlet opening comprising an internal passageway for receiving air flow from the base and an outlet , through which the air stream is released, the outlet opening substantially expanding orthogonally around the axis to define the opening, wherein the air from the surroundings of the ventilation assembly is drawn in through the air stream from the outlet, in which the outlet opening and base have a depth in the direction of the axis, and characterized in that the base depth is no more than twice the depth of the outlet opening, and the outlet opening comprises a Coanda surface adjacent to the outlet and above which the outlet is positioned to direct the air flow.

[0011] Preferably, the base depth is in the range 100 mm to 200 mm, more preferably about 150 mm. In this arrangement it is preferred that the ventilation assembly has a height extending from the end of the base distant from the outlet opening to the end of the outlet opening distant from the base, and a width perpendicular to the height, both height and width being perpendicular to said axis, and whose base width is not more than 75% of the width of the outlet opening.

[0012] The invention provides a system in which an air current is generated and a cooling effect is created without a blade fan. The bladeless system leads to lower sound emissions due to the lack of sound of the air fan blade and the reduction of moving parts and complexity. The dimensions of the base are small compared to the dimensions of the outlet opening and compared to the size of the entire structure of the ventilation unit. The depth of the base of the ventilation unit is such that the ventilation unit is a narrow product, taking up little space for the user. Preferably, the invention provides a ventilation kit that guarantees a proper cooling effect from a smaller bowl than prior art fans. Advantageously, an assembly with fewer parts than with prior art fans can be created and produced by this system. This reduces production cost and complexity.

[0013] In the following description of fans, and in particular of a fan of a preferred embodiment, the term "bladeless" is used to describe a device in which an air stream is released or ejected forward from a ventilation assembly without the use of blades. According to this definition, the bladeless fan assembly can be considered to have an exit area or emission zone without blades or propellers from which the air stream is released or released in a direction suitable for the user. The bladeless fan assembly may be equipped with a primary air source from a variety of sources or generating devices such as pumps, generators, motors or other liquid transfer devices that include rotary devices such as an engine rotor and a vane rotor for generating an air stream. The air supply generated by the engine creates an air stream flowing from the space of the room or the surrounding of the ventilation unit through the internal corridor to the outlet opening and then through the outlet.

[0014] Therefore, the description of the fan assembly as bladeless is not intended to extend the description of the energy source and components, such as motors, which are required for secondary fan functions. Examples of secondary fan functions may include lighting, adjustment and oscillation of the fan.

[0015] Preferably, the width of the base of the ventilation assembly is in the range of 65% to 55% of the width of the outlet, more preferably about 50% of the width of the outlet. In a preferred embodiment, the height of the fan assembly is in the range of 300 mm to 400 mm, more preferably about 350 mm. Advantageous features and dimensions of the ventilation unit result in a compact system, generating at the same time an adequate amount of air stream from the ventilation unit to cool the user.

[0016] It is preferred that the base is substantially cylindrical. This arrangement creates a ventilation unit with a compact base that looks solid and uniform. This type of bare appearance is desirable and often appeals to the user or customer. In addition, when located on a desk or work surface, the surface area of ​​the desk occupied by the base of the ventilation assembly is smaller than the surface occupied by other known ventilation assemblies. The outlet takes up space above the desk surface, widening from the base without obscuring the desk surface or interfering with user access to the desk surface.

[0017] Preferably the base has at least one air inlet arranged substantially orthogonally to the axis. Preferably, the base has a side wall comprising said at least one air inlet. Arranging the air inlets around the base provides flexibility in the base and outlet opening and allows air to flow to the base from multiple points, thus allowing more air to flow to the assembly as a whole. More preferably, said at least one air inlet comprises a plurality of air inlets extending about a second axis substantially orthogonal to said first axis. In this arrangement, it is preferred that the assembly has a stream path extending from each air inlet to the inlet to the air flow developing device through the outlet opening in which the inlet to the air flow developing device is substantially orthogonal to the inlet or each of the air inlets. The system guarantees an inlet air path that minimizes noise and frictional losses in the system.

[0018] The outlet includes a Coanda surface adjacent the outlet and over which the outlet is directed to direct the air flow. The Coanda surface is a known type of surface over which a stream of fluid exiting the outlet near the surface exhibits a Coanda effect. Fluid generally flows close above the surface, almost 'clinging to' or 'hugging' the surface. The Coanda effect is already a proven, well-documented method of induction, as a result of which the main air stream is directed above the Coanda surface. A description of the Coanda surface properties and fluid flow effect above the Coanda surface can be found in articles such as Reba, Scientific American, Volume 214, June 1963, pages 84 to 92. By using a Coanda surface, air from the surroundings of the ventilation unit is drawn through the opening by means of a stream of air directed above the Coanda surface.

[0019] In the present invention, the air stream is generated through the outlet opening of the ventilation assembly. In the following description, this air stream will be called the main air stream. The main air stream exits the outlet opening through the outlet and preferably passes over the Coanda surface. The main air stream enters the air surrounding the outlet of the outlet opening, which acts as an air stream amplifier, providing both the main air stream and the air that enters the user. The air that has entered will be referred to as the secondary air stream. The secondary air flow is taken from the room space, region or external environment surrounding the outlet opening and, by displacement, from other regions around the ventilation assembly. The main stream of air directed above the Coanda surface in connection with the secondary stream of air entering the air stream amplifier, give the whole stream of air released or ejected to the user from the opening defined by the outlet opening. The entire air flow is sufficient for the ventilation assembly to create an air current suitable for cooling.

[0020] The advantage of the air current supplied by the ventilation assembly to the user is that it is a low turbulence air flow and with a more linear air flow profile than that guaranteed by other prior art devices. The linear air flow with low turbulence effectively escapes from the emission point and loses less energy and less speed to turbulence than the air flow generated by prior art fans. The advantage for the user is that the cooling effect can be felt even at a distance and the overall efficiency of the fan increases. This means that the user can decide to place the fan at a distance from the workplace or desk and can still feel the cooling properties of the fan.

[0021] Preferably, the assembly results in the induction of air surrounding the outlet of the outlet in such a way that the main air flow is amplified by at least 15%, while the overall outflow is smooth. The induction and strengthening properties of the ventilation assembly give a fan with higher efficiency than the state of the art devices. The air current released from the opening defined by the outlet opening has an approximately flat velocity profile over the entire diameter of the outlet opening. In general, the stream rate and profile can be described as a piston stream, with some regions having a layered or partially layered stream.

[0022] Preferably the outlet includes a loop. The shape of the outlet opening is not limited by the need to provide space for a blade fan. In a preferred embodiment, the outlet is annular. By guaranteeing an annular outlet, the fan can potentially reach a wide area. In a further preferred embodiment, the outlet is at least partially circular. This arrangement can guarantee a variety of fan appearance options, increasing the choice available to the user or customer.

[0023] Preferably, the interior corridor is continuous, more preferably significantly annular. This allows for a smooth, unhindered air flow within the outlet opening and reduces noise and loss due to friction. In this arrangement, the outlet can be made as a single element, reducing the complexity of the ventilation assembly and thereby reducing production costs.

[0024] In a preferred fan arrangement, the device for causing an air flow through the outlet opening is to cause an air flow through the outlet opening having a pressure of at least 400 kPa. Such pressure is sufficient to overcome the pressure created by the restriction caused by the outlet of the outlet opening and gives an outlet air pressure suitable for cooling the user. More preferably, in use, the rate of mass air stream discharged from the ventilation assembly is at least 450 l / s, most preferably in the range of 600 l / s to 700 l / s. Advantageously, this mass stream can be ejected forward from the opening and the area surrounding the outlet of the outlet with the layered stream and can be perceived by the user as a better cooling effect than in the case of a blade fan.

[0025] In a preferred fan arrangement, the device for causing air flow through the outlet opening comprises a motor-driven impeller. This system provides a fan with effective air flow generation. More preferably, the device for causing the airflow comprises a brushless DC motor and a mixed jet impeller. This

- The 6th system reduces frictional losses from engine brushes, and also reduces carbon particles from brushes in a traditional engine. Reducing particles and carbon emissions is beneficial in a clean or sensitive environment, such as a hospital or in an allergy environment.

[0026] The outlet may rotate or rotate about an axis relative to the base part or other part of the fan assembly. This enables the outlet to be directed towards the user or from the user as required. The ventilation unit can be mounted on a desk, floor, wall or ceiling. This can increase the part of the room where the user experiences cooling.

[0027] The outlet may be substantially annular. By providing a substantially annular outlet, the total air flow can be released towards the user over a wide area. Preferably, the lighting source in the room or at the location of the desk fan or daylight can reach the user through the central opening. The outlet can be concentric with the internal corridor. This arrangement will be visually attractive, and the concentric location of the outlet with the corridor will facilitate production.

[0028] An embodiment of the invention will now be described with reference to the accompanying drawings, in which:

Figure 1 is a front view of the ventilation assembly;

Figure 2 is a perspective view of a part of the ventilation assembly of Figure 1;

Figure 3 is a side cross-section through part of the ventilation assembly of Figure 1 along the line AA;

Figure 4 is an enlarged side cross-section of a part of the ventilation assembly of Figure 1; and

Figure 5 is a cross-sectional view of the ventilation assembly along line BB of Figure 3 and seen from the direction of F in Figure 3.

[0029] Figure 1 shows an example of the ventilation assembly 100 seen from the front of the device. Ventilation assembly 100 includes an annular outlet opening 1 defining a central opening 2. Also referring to Figures 2 and 3, outlet opening 1 includes an internal passage 10, outlet 12 and Coanda surface 14 adjacent to outlet 12. The surface of Coanda 14 is arranged in such a way that the main air stream coming out through the outlet 12 and directed above the surface of Coanda 14 is amplified by the Coanda effect. The outlet 1 is connected to the base 16 and supported by the base 16 having an outer casing

18. The base 16 includes a plurality of selection buttons 20, accessible through the outer casing 18, and with which the ventilation assembly 100 can be operated. The ventilation assembly has the height, width and depth, shown in Figures 1 and 3. The outlet opening 1 is arranged so that it extends substantially orthogonally around the X axis. The height of the venting assembly, H, is perpendicular and extends from the end of base 16 distant from outlet 1 to the end of outlet 1 distant from base 16. In this embodiment, the ventilation assembly 100 has a height, H, about 530 mm, but the ventilation assembly 100 may have the desired height, e.g., about 475 mm. The base 16 and the outlet 1 have a width perpendicular to the height H and perpendicular to the X axis. The width of the base 16 is shown with the designation W1, and the width of the outlet 1 is shown with the designation W2 in Figure 1. The base 16 and the outlet 1 have a depth in the direction of the X axis. The depth of the base 16 is shown with the designation D1 and the depth of the outlet 1 is shown with the designation D2 in Figure 3.

[0030] Figures 3, 4 and 5 show further details of the fan assembly 100. A motor 22 for causing airflow through the outlet 1 is located inside the base 16. The base 16 is substantially cylindrical and in this embodiment the base 16 has a diameter (i.e. width W1 and depth D1) about 45 mm. The base 16 further includes air inlets 24a, 24b formed in the outer housing 18. The engine housing 26 is located inside the base 16. The motor 22 is supported by the motor housing 26 and held in a secure position by a rubber mount or sealing member 28.

[0031] In the embodiment shown, the motor 22 is a DC brushless motor. The rotor 30 is connected to a rotating shaft extending outward from the motor 22, and the diffuser 32 is positioned with the rotor 30 current. The diffuser 32 comprises a fixed stationary disk having spiral wings.

The inlet 34 to the rotor 30 communicates with the air inlets 24a, 24b formed in the outer housing 18 of the base 16. The outlet 36 of the diffuser 32 and the exhaust gas from the rotor 30 communicate with the empty parts of the corridors or channels located inside the base 16 to form a stream air from the impeller 30 to the internal passage 10 of the outlet 1. The motor 22 is connected to the electrical connector and power source and is controlled by a control device (not shown). Communication between the control device and the multiple selection buttons 20 allows the user to operate the ventilation assembly 100.

[0033] The properties of the outlet 1 will now be described with reference to Figures 3 and 4. The shape of the outlet 1 is annular. In this embodiment, the outlet opening 1 has a diameter of about 350 mm, but the outlet opening can have any desired diameter, e.g. about 300 mm. The internal corridor 10 is annular and is formed as a continuous loop or duct within the outlet opening 1. The outlet 1 is formed of at least one wall defining an internal passage 10 and an outlet 12. In this embodiment, the outlet 1 comprises an inner wall 38 and an outer wall 40. In the embodiment shown, the walls 38, 40 are arranged in a spiral or corrugated shape, so that the inner wall 38 and the outer wall 40 approach each other. The inner wall 38 and the outer wall 40 together define the outlet 12 and the outlet 12 extends around the X axis. The outlet 12 comprises a narrowed region 42, tapering to the exit 44. Output 44 includes a gap or gap formed between the inner wall 38 of the outlet opening 1 and the outer wall of the outlet opening 1. The distance between the opposite walls 38, 40 of the outlet 44 of the outlet 12 is selected in the range from 1 mm to 5 mm. The choice of the distance depends on the features of the desired fan operation. In this embodiment, the exit 44 is about 1.3 mm wide, and the outlet 12 and the exit 44 are concentric with the internal passage 10.

[0034] The outlet 12 adjoins the Coanda surface 14. The outlet opening 1 of the illustrated embodiment includes part of a diffuser positioned with the Coanda surface current. Part of the diffuser includes the surface of the diffuser 46, further supporting the flow of current of the supplied air or the exit of the venting assembly 100. In the example shown in Figure 3, the outlet 12 and the overall arrangement of the outlet 1 is such that the angle between the Coanda surface and the X axis is about 15 °. This angle is chosen for the effective air flow over the Coanda surface 14. The outlet opening 1 extends about 5 cm in the direction of the axis. The surface of the diffuser 46 and the general profile of the outlet opening 1 are based on the shape of the support panel, and in the example presentation part of the diffuser extends to a distance of about two thirds of the overall depth of the outlet opening 1.

[0035] The venting assembly 100 described above operates as follows. When the user makes the right choice among a plurality of buttons 20 for operating or activating the venting assembly 100, a signal or other message is sent to start the engine 22. The engine 22 is therefore activated and air is drawn into the venting assembly 100 through the air inlet 24a, 24b . In a preferred embodiment, air is drawn in at a rate of about 20 to 30 liters per second, preferably about 27 l / s (liters per second). The air passes through the outer casing 18 and along the path represented by the arrow F 'of Figure 3 to the inlet 34 of the impeller 30. The air flow exiting through the outlet 36 of the diffuser 32 and the exhaust gas of the impeller 30 are divided into two air streams that proceed in opposite directions through the internal passage 10 . The air flow is obstructed as it enters through outlet 12 and is further compressed at outlet 44 of outlet 12. Compression creates pressure in the system. The engine 22 creates an air stream through the outlet opening 1 having a pressure of at least 400 kPa. The developed air stream overcomes the pressure created by the compression and the air stream exits through the outlet 44 as the main air stream.

[0036] The output and emission of the main air stream creates a low pressure area at the air inlets 24a, 24b with the effect of drawing additional air into the ventilation assembly 100. The operation of the ventilation assembly 100 causes a high air flow through the outlet 1 and from the opening 2. The main air stream is directed above the Coanda surface 14 and the surface of the diffuser 46 and is enhanced by the Coanda effect. The secondary air flow is generated by the induction of ambient air, particularly from the region around the outlet 44 and around the outer edge of the outlet opening 1. Part of the secondary air flow induced by the main air flow can also be directed above the surface of the diffuser 46. This secondary air flow passes through orifice 2, where it joins the main air stream to create the total air stream ejected from the outlet orifice 1.

[0037] The combination of induction and amplification results in the total air flow from the opening 2 of the ventilation unit 100, which is larger than the output of the air stream from the ventilation unit without such a Coanda surface or reinforcement surface adjacent to the emission area.

[0038] The reinforcement and the linear type of the resulting air stream results in an uninterrupted air flow directed towards the user from the outlet opening 1. In a preferred embodiment, the mass flow rate of the air ejected from the venting assembly 100 is at least 450 l / s, preferably at range from 600 l / s to 700 l / s. The flow rate at a distance of up to 3 outlet diameters (i.e. around 1000 to 1200 mm) from the user is around 400 to 500 l / s. The total air flow has a speed of about 3 to 4 m / s (meters per second). Higher speeds are achieved by reducing the angle between the Coanda surface 14 and the X axis. A smaller angle results in the total air stream being released in a more focused and directed manner. This type of air stream is usually released at a higher speed but at a reduced mass flow rate. Conversely, greater mass flow can be achieved by increasing the angle between the Coanda surface and the axis. In this case, the velocity of the exhaust air stream is reduced, but the mass flow generated increases. From here, you can change the operation of the ventilation assembly by changing the angle between the Coanda surface and the X axis.

[0039] The invention is not limited to the detailed description given above. The differences will be obvious to a person specialized in this field. For example, the fan could be of a different height or diameter. The fan base and outlet could have different depth, width and height. The fan does not have to be placed on the desk, but it could be free standing, mounted on a wall or ceiling. The fan shape can be adapted to any type of situation or location where a cooling air flow is desired. A portable fan could have a smaller outlet, say 5 cm in diameter. The device for causing the air flow through the outlet opening may be a motor or other venting device, such as a blower or a suction device, which can be used so that the ventilation assembly can create an air current in the room. Examples include a motor such as an AC induction motor or DC brushless motor types, but may also include any suitable air movement or air transport device, such as a pump or other device providing a directed flow of liquid to generate and cause air flow. Engine features may include a diffuser or a secondary diffuser arranged with the motor current to recover some of the static pressure lost in the motor housing and by the motor.

[0040] The outlet output can be modified. The outlet output can be widened or narrowed to different values ​​to maximize airflow. The air stream emitted through the outlet may pass over a surface, such as a Coanda surface, alternatively the air stream may be emitted through the outlet and ejected from the venting assembly without passing over the adjacent surface. You can make the Coanda effect appear over many different surfaces, or you can use a combination of many internal or external solutions to achieve the required air flow and induction.

[0041] Other shapes of vent are anticipated. For example, one may use a vent, oval or "stadium" shaped, of a single lane or line, or

- 10 solid shape. The ventilation assembly provides access to the central part of the fan as there are no blades. This means that additional features such as lighting or a clock or LCD display could be present in the opening defined by the outlet opening.

[0042] Other features could include a base rotating about its axis or tilting to help the user move and adjust the position of the outlet opening.

Prepared and verified

Jolanta Górczak Patent Attorney